it's not there for me neither.
but to be honest untill I checked (about a minute ago) I forgot there is a gallery
but if you want to watch the scene you can just load up an older save or something.
also it does not count as a sex scene so that is probably the reason why it's not in the gallery. or it's a bug and will be fixed in the next version.
hey, there is a scene with Jade that you can no longer acces unless you have an older version so there's that